1. Field of Invention
The present invention relates to an audio amplifier. More particularly, the present invention relates to a class D audio amplifier.
2. Description of Related Art
An audio system generally consists of three parts. The first part is an audio source, such as a tape player, a disc player or an RF tuner, for retrieving audio information and converting it into an electrical signal. The second part of the audio system is a loudspeaker. The loudspeaker converts electrical signals into acoustic waves to be perceived by a listener. The third part of the audio system is a power amplifier. The power amplifier amplifies the electrical signals from the audio source and supplies the necessary current to drive the loudspeaker.
However, an overly high DC current is often suddenly generated and also flows into the load, i.e. loudspeaker, when the power is turned on to start the audio power amplifier. Therefore, the load could be damaged because of the suddenly generated DC current, and a popping noise is also produced at the same time based on the suddenly generated DC current.